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Maria Papathoma-Köhle and Dale Dominey-Howes

Risk and vulnerability indicators at different scales: Applicability, usefulness and policy implications. Environmental Hazards 7 20— Bollin C, Hidajat R Community-based disaster risk index: pilot implementation in Indonesia. In: Birkmann, J. Breheny, P. Dissertation, University of Leeds, United Kingdom. The increasing wildfire and post-fire debris-flow threat in Western USA, and implications for consequences of climate change.

Landslides - disaster risk reduction, Springer Verlag, CAPRA A methodological approach for the definition of multi-risk maps at regional level: first application. Journal of Risk Research, — DeGraff, J. Washington, D. XVI, No. Producing landslide-susceptibility maps for regional planning in data-scarce regions. Nat Hazards — DeGraff JV Solving the dilemma of transforming landslide hazard maps into effective policy and regulations, Nat. Hazards Earth Syst. Deliverable 3. Report on new methodology for multi-risk assessment and the harmonisation of different natural risk maps.

Coastal hazard assessment and mapping in Northern Campania, Italy. Geomorphology, — EC Risk assessment and mapping guidelines for disaster management. European Commission Commission staff working paper, European Union. FEMA Garcia-Aristizabal A, Marzocchi W Software for multi-hazard assessment. Community risk in Cairns: a multi-hazards risk assessment. Beijing: Integrated Research on Disaster Risk. An overview of quantitative risk measures and their application for calculation of flood risk.

Challenges of analyzing multi-hazard Risk: A Review. Natural Hazards 64 2 , Event tree analysis of Aknes rock slide hazard. Lee K and Rosowsky D Fragility analysis of woodframe buildings considering combined snow and earthquake loading. Structural Safety, Luino F Sequence of instability processes triggered by heavy rainfall in the northern Italy. Principles of multi-risk assessment: interactions amongst natural and man-induced risks. European Commission. Organization of American States.

Peila D, Guardini C Use of the event tree to assess the risk reduction obtained from rockfall protection devices. Problems and challenges in analyzing multiple territorial risks. Prinos P Review of Flood Hazard Mapping. Quantification of vulnerability to natural hazards. Roobol, M. Quantitative multi-risk analysis for natural hazards: a framework for multi-risk modelling.


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Natural Hazards 58 3 , Natural Hazards Review 7 2 , Study on the risk assessment and risk transfer mode of large scale disasters. Spatial pattern of hazards and hazard interactions in Europe. Terminology on Disaster risk Reduction. Malet, T. Glade and N.

ISBN Van Westen CJ Remote sensing and GIS for natural hazards assessment and disaster risk management. This book, with contributions from international landslide experts, presents in-depth knowledge of theories, practices, and modern numerical techniques for landslide analysis. Landslides are a reoccurring problem across the world and need to be …. This edited volume assesses capabilities of data mining algorithms for spatial modeling of natural hazards in different countries based on a collection of essays written by experts in the field.

The book is organized on different hazards including …. This book covers the restoration and reconstruction process and activities undertaken in Japan in the first five years since the Earthquake and Tsunami — a period widely considered to be the most intensive reconstruction phase within the …. These chapters provide valuable and comprehensive information on a variety of hazards, including both scientific and social aspects of disasters. The work introduces the concept of large, medium and small scale hazards, and includes many useful …. This book gathers the most recent scientific research on the geological, geotechnical and geophysical aspects of slope failure in sensitive clays.

Gathering contributions by international experts, it focuses on understanding the complete and …. This book is a comprehensive collection of state-of-the-art studies of seafloor slope instability and their societal implications. The volume captures the most recent and exciting scientific progress made in this research field. This edited volume emphasizes risk and crisis communication principles and practices within the up-to the minute context of new technologies, a new focus on resiliency, and global environmental change.

It includes contributions from experts from a. It provides further evidence that ecosystem-based approaches make economic sense, and …. Methods which can be used for an assessment are summarized in table Graphic description of failure sequences and mathematical calculation of probabilities.

Use of scenario ensembles for deriving seismic risk

A component has to withstand the following: static loads, dynamic loads, internal and external pressure, corrosion, loads arising from large differences in temperature, loads arising from external impacts wind, snow, earthquakes, settling. Design standards are therefore a minimum requirement as far as major hazard installations are concerned. When an installation is designed to withstand all loads that can occur during normal or foreseen abnormal operating conditions, it is the task of a process control system to keep the plant safely within these limits.

In order to operate such control systems, it is necessary to monitor the process variables and active parts of the plant. Operating personnel should be well trained to be aware of the mode of operation and the importance of the control system. To ensure that the operating personnel do not have to rely solely on the functioning of automatic systems, these systems should be combined with acoustic or optical alarms. It is most important to realize that any control system will have problems in rare operating conditions such as start-up and shut-down phases.

Special attention must be paid to these phases of operation. Quality control procedures will be audited by management periodically. Any major hazard installation will require some form of safety system. The form and design of the system depend on the hazards present in the plant. The following gives a survey of available safety systems:.

The safety of a plant and the function of a safety-related system can only be as good as the maintenance and monitoring of these systems. It is necessary to establish a plan for onsite inspections, for the operating personnel to follow, which should include a schedule and the operating conditions to be adhered to during inspection work. Strict procedures must be specified for carrying out repair work. As people can have a negative as well as a positive influence on plant safety, it is important to reduce the negative influences and support the positive ones. Even if a hazard assessment has been carried out and the hazards have been detected and appropriate measures to prevent accidents have been taken, the possibility of an accident cannot be completely ruled out.

For this reason, it must be part of the safety concept to plan and provide measures which can mitigate the consequences of an accident. These measures have to be consistent with the hazards identified in the assessment. Furthermore, they must be accompanied by proper training of plant personnel, the emergency forces and responsible representatives from public services.

Only training and rehearsals of accident situations can make emergency plans realistic enough to work in a real emergency. Depending on local arrangements in different countries, employers of a major hazard installation shall report to the appropriate competent authority. Reporting may be carried out in three steps. These are:. Workers and their representatives shall be consulted through appropriate cooperative mechanisms in order to ensure a safe system of work. They shall be consulted in the preparation of, and have access to, safety reports, emergency plans and procedures, and accident reports.

They shall receive training for preventing major accidents and in emergency procedures to be followed in the event of a major accident. Finally, workers and their representatives should be able to take corrective action where needed within the scope of their duties, if they believe that there is any imminent danger of a major accident. They also have the right to notify the competent authority of any hazard. Workers shall comply with all practices and procedures for preventing major accidents and for the control of developments likely to lead to a major accident.

They shall comply with all emergency procedures should a major accident occur. Although the storage and use of large quantities of hazardous materials is widespread across most countries of the world, the present systems for their control will differ substantially from one country to another.

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This means that the speed of implementation of a major hazard control system will depend on the facilities already existing in each country, particularly with regard to trained and experienced facility inspectors, together with the resources available locally and nationally for the different components of the control system.

For all countries, however, implementation will require the setting of priorities for a stage-by-stage programme. Any definition for identifying major hazards is likely to involve a list of hazardous materials, together with an inventory for each, such that any major hazard installation storing or using any of these in excess quantities is by definition a major hazard installation.

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The next stage is to identify where the major hazard installation exists for any particular region or country. Where a country wishes to identify major hazard installations before the necessary legislation is in place, considerable progress can be achieved informally, particularly where the cooperation of industry is available.

Existing sources such as factory inspectorate records, information from industrial bodies and so on, may enable a provisional list to be obtained which, apart from allowing early inspection priorities to be allocated, will enable an assessment to be made of the resources required for different parts of the control system. For countries considering establishing a major hazard control system for the first time, an important first stage is likely to be setting up a group of experts as a special unit at government level.

The group will have to set priorities in deciding on its initial programme of activity.

The group may be required to train factory inspectors in the techniques of major hazard inspection, including operational standards for such major hazard installations. They should also be able to provide advice about the siting of new major hazards and the use of land nearby. They will need to establish contacts in other countries in order to keep up to date with major hazard developments.

Emergency plans require that the major hazard installation be assessed for the range of accidents that could take place, together with how they would be tackled in practice. The handling of these potential accidents will require both staff and equipment, and a check should be made to ensure that both are available in sufficient numbers.

The plans should include the following elements:. This is an area which has received less attention than onsite emergency planning, and many countries will be faced with considering this for the first time. The offsite emergency plan will have to link the possible accidents identified by the major hazard installation, their expected likelihood of occurrence and the proximity of people living and working nearby.

It must have addressed the need for the expeditious warning and evacuation of the public, and how these might be achieved. It should be remembered that conventional housing of solid construction offers substantial protection from toxic gas clouds, whereas a shanty-type house is vulnerable to such accidents. The emergency plan must identify organizations whose help will be required in the event of an emergency and must ensure that they know what role is expected of them: hospitals and medical staff should, for example, have decided how they would handle large numbers of casualties and in particular what treatment they would provide.

The offsite emergency plan will need to be rehearsed with public involvement from time to time. Where a major accident could have transboundary effects, full information is to be provided to the jurisdictions concerned, as well as assistance in cooperation and coordination arrangements. The basis for needing a siting policy for major hazard installations is straightforward: since absolute safety cannot be guaranteed, major hazard installations should be separated from people living and working outside the facility.

As a first priority, it may be appropriate to concentrate efforts on proposed new major hazards and to try to prevent the encroachment of housing, particularly shanty houses, which are a common feature in many countries. The role of the facility inspectors is likely to be central in many countries in implementing a major hazard control system. Facility inspectors will have the knowledge that will enable early identification of major hazards to take place. Where they have specialist inspectors to call upon, factory inspectors will be assisted in the often highly technical aspects of major hazard inspection.

Inspectors will need appropriate training and qualifications to aid them in this work. Industry itself is likely to be the largest source of technical expertise within many countries, and may be able to provide assistance in facility inspectorate training. This should be carried out by specialists, if possible according to guidelines drawn up, for example, by the group of experts or by specialist inspectors, possibly with assistance from the major hazard installation employer management group.

Evaluation involves a systematic study for major accident hazard potential. It will be a similar exercise, although in much less detail, to that carried out by the major hazard installation management in producing its safety report for the facility inspectorate and in establishing an onsite emergency plan. Evaluation will include a study of all handling operations of hazardous materials, including transport.

An examination of the consequences of process instability or major changes in the process variables will be included. The evaluation also should consider the positioning of one hazardous material in relation to another. The evaluation will consider the consequences of the identified major accidents in relation to offsite populations; this may determine whether the process or plant can be put into operation. Experience of major accidents, particularly those involving toxic gas releases, has shown the importance of the public nearby having prior warning of: a how to recognize that an emergency is occurring; b what action they should take; and c what remedial medical treatment would be appropriate for anyone being affected by the gas.

For inhabitants of conventional housing of solid construction, the advice in the event of an emergency usually is to go indoors, close all doors and windows, switch off all ventilation or air conditioning, and switch on the local radio for further instructions. Where large numbers of shanty-dwellers live close to a major hazard installation, this advice would be inappropriate, and large-scale evacuation might be necessary. A fully developed major hazard control system requires a wide variety of specialized personnel. Apart from industrial staff concerned either directly or indirectly with the safe operation of the major hazard installation, required resources include general factory inspectors, specialist inspectors, risk assessors, emergency planners, quality control officers, local authority land planners, police, medical facilities, river authorities and so on, plus legislators to promulgate new legislation and regulations for major hazard control.

In most countries, human resources for these tasks are likely to be limited, and the setting of realistic priorities is essential. A feature of establishing a major hazard control system is that much can be achieved with very little equipment. Factory inspectors will not need much in addition to their existing safety equipment. What will be required is the acquisition of technical experience and knowledge and the means to relay this from the group of experts to, say, the regional labour institute, the facility inspectorate and the industry.

Additional training aids and facilities may be necessary. A key element in establishing a major hazard control system is obtaining state-of-the-art information and quickly passing this information on to all those who will need it for their safety work. The volume of literature covering the various aspects of major hazards work is now considerable, and, used selectively, this could provide an important source of information to a group of experts.

When, in an exporting member country, the use of hazardous substances, technologies or processes is prohibited as a potential source of a major accident, the information on this prohibition and the reasons for it shall be made available by the exporting member country to any importing country. Certain non-binding recommendations flowed from the Convention. In particular, one had a transnational focus. It recommends that a national or a multinational enterprise with more than one establishment or facility should provide safety measures relating to the prevention of major accidents and the control of developments likely to lead to a major accident, without discrimination, to the workers in all its establishments, regardless of the place or country in which they are situated.

Following serious incidents in the chemical industry in Europe in the last two decades, specific legislation covering major hazard activities was developed in various countries in Western Europe. A key feature in the legislation was the obligation of the employer of a major hazard industrial activity to submit information about the activity and its hazards based on the results of systematic safety studies. After the accident in Seveso Italy in , the major hazard regulations in the various countries were put together and integrated in an EC Directive.

This Directive, on the major accident hazards of certain industrial activities, has been in force since and is often referred to as the Seveso Directive Council of the European Communities , For the purpose of identifying major hazard installations, the EC Directive uses criteria based on the toxic, flammable and explosive properties of the chemicals see table Explosive substances: Substances which may explode under the effect of flame or which are more sensitive to shocks or friction than dinitrobenzene.

For the selection of specific major hazard industrial activities, a list of substances and threshold limits is provided in annexes to the Directive. An industrial activity is defined by the Directive as the aggregate of all installations within a distance of metres of each other and belonging to the same factory or plant. When the quantity of the substances present exceeds the given threshold limit appearing in the list, the activity is referred to as a major hazard installation.

The list of substances consists of chemicals, whereas the threshold limits vary between 1 kg for extremely toxic substances to 50, tonnes for highly flammable liquids. For isolated storage of substances, a separate list of a few substances is given. In addition to flammable gases, liquids and explosives, the list contains chemicals such as ammonia, chlorine, sulphur dioxide and acrylonitrile.

In order to facilitate the application of a major hazard control system and to encourage the authorities and management to apply it, it must be priority oriented, with attention being focused on the more hazardous installations. A suggested list of priorities is given in table If the list is still too big to be coped with by the authorities, new priorities can be set by means of setting new quantity thresholds. Priority setting also can be used inside the factory to identify the more hazardous parts. In view of the diversity and complexity of industry in general, it is not possible to restrict major hazard installations to certain sectors of industrial activity.

Experience, however, indicates that major hazard installations are most commonly associated with the following activities:. Over the last two decades the emphasis in disaster reduction has switched from mainly improvised relief measures in the post-impact phase to forward planning, or disaster preparedness. The following four phases are the components of a comprehensive hazard management plan which can be applied to all types of natural and technological disasters:.

The aim of disaster preparedness is to develop disaster prevention or risk reduction measures in parallel with emergency preparedness and response capabilities. In this process hazard and vulnerability analyses are the scientific activities which provide the basis for the applied tasks of risk reduction and emergency preparedness to be undertaken in collaboration with planners and the emergency services.

Most health professionals would see their role in disaster preparedness as one of planning for the emergency treatment of large numbers of casualties. However, if the impact of disasters is to be drastically reduced in the future, the health sector needs to be involved in the development of preventive measures and in all phases of disaster planning, with scientists, engineers, emergency planners and decision makers.

This multidisciplinary approach poses a major challenge to the health sector at the end of the 20th century as natural and human-made calamities become increasingly destructive and costly in terms of lives and property with the expansion of human populations across the globe. Natural sudden or rapid-onset disasters include extreme weather conditions floods and high winds , earthquakes, landslides, volcanic eruptions, tsunamis and wild fires, and their impacts have much in common.

Famines, drought and desertification, on the other hand, are subject to more long-term processes which at present are only very poorly understood, and their consequences are not so amenable to reduction measures. Presently the most common cause of famine is war or so-called complex disasters e. Large numbers of displaced persons are a common feature of natural and complex disasters, and their nutritional and other health needs require specialized management. Modern civilization is also becoming accustomed to technological or human-made disasters such as acute air pollution episodes, fires and chemical and nuclear reactor accidents, the last two being the most important today.

This article will focus on disaster planning for chemical disasters, as nuclear power accidents are dealt with elsewhere in the Encyclopaedia. The most important of these in terms of destructiveness are floods, hurricanes, earthquakes and volcanic eruptions. There have already been some well-publicized successes in disaster reduction through early warning systems, hazard mapping and structural engineering measures in seismic zones.

Disaster risk reduction - Wikipedia

Thus satellite monitoring using global weather forecasting, together with a regional system for timely delivery of warnings and effective evacuation planning, was responsible for the comparatively small loss of life just 14 deaths when Hurricane Hugo, the strongest hurricane so far recorded in the Caribbean, struck Jamaica and the Cayman Islands in In adequate warnings provided by Philippine scientists closely monitoring Mount Pinatubo saved many thousands of lives through timely evacuation in one of the largest eruptions of the century.

The large human and economic losses wrought by disasters in developing countries highlight the major importance of socio-economic factors, above all poverty, in increasing vulnerability, and the need for disaster preparedness measures to take these into account.


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Natural disaster reduction has to compete in all countries with other priorities. Clearly, with natural hazards it is impossible to prevent the actual geological or meteorological process from occurring. However, with technological hazards, major inroads into disaster prevention can be made using risk reduction measures in the design of plants and governments can legislate to establish high standards of industrial safety.

The Seveso Directive in EC countries is an example which also includes requirements for the development of onsite and offsite planning for emergency response. Major chemical accidents comprise large vapour or flammable gas explosions, fires, and toxic releases from fixed hazardous installations or during the transport and distribution of chemicals.

Special attention has been given to the storage in large quantities of toxic gases, the most common being chlorine which, if suddenly released due to the disruption of a storage tank or from a leak in a pipe, can form large denser-than-air clouds which can be blown in toxic concentrations for large distances downwind. Computer models of dispersion of dense gases in sudden releases have been produced for chlorine and other common gases and these are used by planners to devise emergency response measures. These models can also be used to determine the numbers of casualties in a reasonably foreseeable accidental release, just as models are being pioneered for predicting the numbers and types of casualties in major earthquakes.

A disaster is any disruption of the human ecology that exceeds the capacity of the community to function normally. It is a qualitative difference in that the demands cannot be adequately met by a society without help from unaffected areas of the same or another country. The word disaster is too often used loosely to describe major incidents of a highly publicized or political nature, but when a disaster has actually occurred there may be a total breakdown in normal functioning of a locality. The aim of disaster preparedness is to enable a community and its key services to function in such disorganized circumstances in order to reduce human morbidity and mortality as well as economic losses.

Large numbers of acute casualties are not a prerequisite for a disaster, as was shown in the chemical disaster at Seveso in when a massive evacuation was mounted because of fears of long-term health risks arising from ground contamination by dioxin. Disaster prevention cannot take place in a vacuum, and it is essential that a structure exists at the national governmental level of every country the actual organization of which will vary from country to country , as well as at the regional and community level. In countries with high natural risks, there may be few ministries which can avoid being involved.

The responsibility for planning is given to existing bodies such as armed forces or civil defence services in some countries. Where a national system exists for natural hazards it would be appropriate to build on to it a response system for technological disasters, rather than devise a whole new separate system. Launched in cooperation with industry and government, the programme aims to prevent technological accidents and reduce their impacts in developing countries by raising community awareness of hazardous installations and providing assistance in developing emergency response plans.

The different types of natural disaster and their impacts need to be assessed in terms of their likelihood in all countries. Some countries such as the UK are at low risk, with wind storms and floods being the main hazards, while in other countries e. Each hazard requires a scientific evaluation which will include at least the following aspects:. Areas at high risk of earthquakes, volcanoes and floods need to have hazard zone maps prepared by experts to predict the locations and nature of the impacts when a major event occurs.

Such hazard assessments can then be used by land-use planners for long-term risk reduction, and by emergency planners who have to deal with the pre-disaster response. However, seismic zoning for earthquakes and hazard mapping for volcanoes are still in their infancy in most developing countries, and extending such risk mapping is seen as a crucial need in the IDNDR. Hazard assessment for natural hazards requires a detailed study of the records of previous disasters in the preceding centuries and exacting geological field work to ascertain major events such as earthquakes and volcanic eruptions in historic or prehistoric times.

Learning about the behaviour of major natural phenomena in the past is a good, but far from infallible, guide for hazard assessment for future events. There are standard hydrological methods for flood estimation, and many flood-prone areas can be easily recognized because they coincide with a well-defined natural flood plain.

For tropical cyclones, records of impacts around coastlines can be used to determine the probability of a hurricane striking any one part of the coastline in a year, but each hurricane has to be urgently monitored as soon as it has formed in order to actually forecast its path and speed at least 72 hours ahead, before it makes landfall. Associated with earthquakes, volcanoes and heavy rains are landslides which may be triggered by these phenomena.

In the last decade it has been increasingly appreciated that many large volcanoes are at risk from slope failure because of the instability of their mass, which has been built up during periods of activity, and devastating landslides may result. With technological disasters, local communities need to make inventories of the hazardous industrial activities in their midst. There are now ample examples from past major accidents of what these hazards can lead to, should a failure in a process or containment occur.

Quite detailed plans now exist for chemical accidents around hazardous installations in many developed countries. After evaluating a hazard and its likely impacts, the next step is to undertake a risk assessment. Hazard may be defined as the possibility of harm, and risk is the probability of lives being lost, persons injured or property damaged due to a given type and magnitude of natural hazard. Risk can be quantitatively defined as:. Ascertaining vulnerability is a key part of risk assessment: for buildings it is the measure of the intrinsic susceptibility of structures exposed to potentially damaging natural phenomena.

For example, the likelihood of a building collapsing in an earthquake can be determined from its location relative to a fault line and the seismic resistance of its structure. In the above equation the degree of loss resulting from the occurrence of a natural phenomenon of a given magnitude can be expressed on a scale from 0 no damage to 1 total loss , while hazard is the specific risk expressed as a probability of preventable loss per unit time.

Vulnerability is therefore the fraction of value that is likely to be lost as a result of an event. The information needed for making a vulnerability analysis can come, for example, from surveys of homes in hazard areas by architects and engineers. Vulnerability assessments utilizing information on different causes of death and injury according to the different types of impact are much more difficult to undertake at the present time, as the data on which to base them are crude, even for earthquakes, since standardization of injury classifications and even the accurate recording of the number, let alone the causes of deaths, are not yet possible.

These serious limitations show the need for much more effort to be put into epidemiological data-gathering in disasters if preventive measures are to develop on a scientific basis. At present mathematical computation of risk of building collapse in earthquakes and from ash falls in volcanic eruptions can be digitalized onto maps in the form of risk scales, to graphically demonstrate those areas of high risk in a foreseeable event and predict where, therefore, civil defence preparedness measures should be concentrated.

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Thus risk assessment combined with economic analysis and cost effectiveness will be invaluable in deciding between different options for risk reduction. In addition to building structures, the other important aspect of vulnerability is infrastructure lifelines such as:. In any natural disaster all of these are at risk of being destroyed or heavily damaged, but as the type of destructive force may differ according to the natural or technological hazard, appropriate protective measures need to be devised in conjunction with the risk assessment.

Geographical information systems are modern computer techniques for mapping different data sets to assist in such tasks. In planning for chemical disasters, quantified risk assessment QRA is used as a tool to determine the probability of plant failure and as a guide for decision makers, by providing numerical estimates of risk. Engineering techniques for making this type of analysis are well advanced, as are the means of developing hazard zone maps around hazardous installations.

Methods exist for predicting pressure waves and concentrations of radiant heat at different distances from the sites of vapour or flammable gas explosions. Computer models exist for predicting the concentration of denser-than-air gases for kilometres downwind from an accidental release in specified amounts from a vessel or plant under different weather conditions. In these incidents vulnerability mainly has to do with the proximity of housing, schools, hospitals and other key installations. Individual and societal risks need to be computed for the different types of disaster and their significance should be communicated to the local population as part of overall disaster planning.

Once vulnerability has been assessed, the feasible measures to reduce vulnerability and overall risk need to be devised. Thus new buildings should be made seismic resistant if built in a seismic zone, or old buildings can be retrofitted so that they are less likely to collapse. The need for good roads as evacuation routes must never be forgotten in land developments in areas at risk of windstorms or volcanic eruptions and a host of other civil engineering measures can be enacted depending upon the situation.

In the longer term the most important measure is the regulation of land use to prevent the development of settlements in hazardous areas, such as flood plains, the slopes of active volcanoes or around major chemical plants. Over-reliance on engineering solutions can bring false reassurance in at-risk areas, or be counterproductive, increasing the risk of rare catastrophic events e. The planning and organization of emergency preparedness should be a task for a multidisciplinary planning team involved at the community level, and one which should be integrated into hazard assessment, risk reduction and emergency response.

In the management of casualties it is now well recognized that medical teams from outside may take at least three days to arrive at the scene in a developing country. As most preventable deaths occur within the first 24 to 48 hours, such assistance will arrive too late. Thus it is at the local level that emergency preparedness should be focused, so that the community itself has the means to begin rescue and relief actions immediately after an event. Providing adequate information to the public in the planning phase should therefore be a key aspect of emergency preparation.

On the basis of the hazard and risk analyses, the means of providing early warning will be essential, together with a system for evacuating people from areas of high risk should an emergency arise. Pre-planning of communications systems between the different emergency services at the local and national levels is necessary and for the effective provision and dissemination of information in a disaster a formal chain of communication will have to be established.

Other measures such as stockpiling emergency food and water supplies in households may be included. A community near a hazardous installation needs to be aware of the warning it may receive in an emergency e. An essential feature of a chemical disaster is the need to be able to rapidly define the health hazard posed by a toxic release, which means identifying the chemical or chemicals involved, having access to knowledge of their acute or long-term effects and determining who, if anyone, in the general population has been exposed. Establishing lines of communication with poison information and chemical emergency centres is an essential planning measure.

Unfortunately it may be difficult or impossible to know the chemicals involved in the event of runaway reactions or chemical fires, and even if it is easy to identify a chemical, knowledge of its toxicology in humans, particularly chronic effects, may be sparse or non-existent, as was found after the release of methyl isocyanate at Bhopal. Yet without information on the hazard, the medical management of casualties and the exposed population, including decisions on the need for evacuation from the contaminated area, will be severely hampered.

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A multidisciplinary team to gather information and to undertake rapid health risk assessments and environmental surveys to exclude contamination of ground, water and crops should be pre-planned, recognizing that all available toxicological databases may be inadequate for decision making in a major disaster, or even in small incidents in which a community believes it has suffered serious exposure. The team should have the expertise to confirm the nature of the chemical release and to investigate its likely health and environmental impacts.

In natural disasters, epidemiology is also important for making an assessment of the health needs in the post-impact phase and for infectious diseases surveillance. Information gathering on the effects of the disaster is a scientific exercise which should also be part of a response plan; a designated team should undertake this work to provide important information for the disaster coordinating team as well as for assisting in the modification and improvement of the disaster plan.

The designation of the emergency service in charge, and the constitution of a disaster coordinating team, will vary from country to country and with the type of disaster, but it needs to be pre-planned. At the scene a specific vehicle may be designated as the command and control, or onsite coordinating centre. For example, emergency services cannot rely on telephone communications, as these may become overloaded, and so radio links will be needed. The capability of hospitals in terms of staff, physical reserves theatres, beds and so on and treatment medicines and equipment for dealing with any major incident will need to be assessed.

Hospitals should have specific plans for dealing with a sudden large influx of casualties, and there should be provision for a hospital flying squad to go to the scene to work with search and rescue teams in extricating trapped victims or to undertake field triage of large numbers of casualties. Major hospitals may be unable to function because of disaster damage, as happened in the earthquake in Mexico City in Restoring or supporting devastated health services may therefore be necessary.

For chemical incidents, hospitals should have established links with poison information centres. As well as being able to draw on a large fund of health care professionals from inside or outside a disaster area to cope with the injured, planning should also include the means for the rapid sending of emergency medical equipment and drugs. The types of search and rescue equipment needed for a specific disaster should be identified at the planning stage along with where it will be stored, as it will need to be rapidly deployed in the first 24 hours, when the most lives can be saved.